What is glycolic acid?

Glycolic acid is one of the most well-known AHAs (alpha hydroxy acids) used in cosmetics. If you're wondering what glycolic acid is, think of it as a chemical exfoliant that acts on the surface of the skin to remove dead cells, accelerate cell renewal and improve texture. All without granules, without friction and with visible results.

It is mainly extracted from sugar cane and stands out for having the smallest molecule of all AHAs. What does this mean? It easily penetrates the skin and works deeper than other similar acids such as lactic or mandelic acid. This makes it very effective, but it also means that you should use it with caution if your skin is sensitive or you are starting out with exfoliants.

To sum up: it's a top ingredient if you're looking for radiance, smoothness and a more even tone, but as with any powerful active ingredient, the secret is knowing how to use it well.

What is it used for?

Glycolic acid acts on several layers of the skin, so its effect goes far beyond removing excess. Here are its main benefits:

Gently exfoliates, dissolving the bonds that hold dead cells together on the skin's surface.
Improves uneven tone and helps fade sun spots, acne marks or post-inflammatory pigmentation.
Helps attenuate fine lines and wrinkles thanks to its action on cell renewal.
Stimulates collagen production, which improves firmness and elasticity.
Brightens the skin, leaving it smoother, more even and with a noticeable glow.

Its effect is cumulative, with regular and correct use, the skin is visibly transformed. But be aware that it is a potent acid and should be used in a careful way, especially at the beginning.

How to use glycolic acid?

Glycolic acid is not tricky to use, but it does require following certain guidelines to avoid irritation and to get the most out of it:

Use it only at night, as it can increase sensitivity to the sun.
Start with a frequency of 1-2 times per week if your skin is not used to it. Then, you can gradually increase if there is no reaction.
Apply after cleansing and before serum or cream. If your skin is sensitive, wait a few minutes until it is completely dry.
It is normal to feel a slight tingling at first, but if bothers, remove it and try a milder formula.
Always use sunscreen the next day. This step is non-negotiable: you are thinning the top layer of your skin and need to protect it well.

Take note: if you are using other actives such as retinol, vitamin C or BHA exfoliants, avoid combining them in the same routine (at least at first). You can alternate them by day to keep your skin stable.

Glycolic acid vs. Retinol

Both ingredients are used to improve skin texture and tone, but have different mechanisms of action:

Glycolic acid exfoliates the surface layer, removing dead cells and improving visible texture.
Retinol acts in deeper layers, stimulating cell renewal from within and promoting collagen production.

You don't have to choose between one or the other: you can use them on alternate nights if your skin tolerates it, or start with one and add the other later. The important thing is to respect the timing and listen to how your skin responds. The key is not to overload it.

How many times a week to use glycolic acid?

The ideal frequency depends a lot on your skin type and your previous experience with exfoliators. Here is a quick guide:

Sensitive or beginner skin: 1 time per week with a low concentration (5% or less).
Normal skin or skin used to acids: 2 times a week, with moderate concentrations.
Oily, resistant or experienced skin: up to 3 times a week, even with higher concentrations, if tolerated.

Tip: do not use it every day, even if your skin tolerates it well. Constant exfoliation can weaken the skin barrier. It's better to maintain a balance that guarantees results without damaging the skin.

In what form should it be used?

You can find glycolic acid in several types of products, and each has a different intensity:

Toners: ideal for starting out. They usually have a low concentration and are applied with cotton or hands.
Serums and ampoules: perfect if you already have experience. They usually have higher concentration and a more powerful action.
Masks or peelings: for occasional treatments. Use with caution and respect exposure times.
Exfoliating cleansers: milder action as they are rinse-off products, good for maintenance.

Choose the format according to your level of experience, and if it is the first time you use glycolic acid, it is better to start with a toner or a cleanser to test tolerance.

What skin type can use it?

In general, glycolic acid can be adapted to almost any skin if the concentration and frequency of use are well chosen:

Oily skin or skin with enlarged pores: helps reduce impurities, cleanse pores and control sebum.
Skin with blemishes or uneven skin tone: visibly improves even tone and luminosity.
Textured or rough skin: helps to smooth and soften the face.
Dry or mature skin: stimulates cell renewal and provides glow, but should be combined with moisturizing ingredients to avoid tightness.

If your skin is very sensitive or you are undergoing dermatological treatment, it is best to consult beforehand or choose milder alternatives such as lactic or mandelic acid.